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401.
Bergersen H Abu-samha M Harnes J Björneholm O Svensson S Saethre LJ Børve KJ 《Physical chemistry chemical physics : PCCP》2006,8(16):1891-1898
Theoretical models of lineshapes in Ar2p photoionization spectra have been calculated for free, neutral argon clusters of different sizes. The lineshape models are fitted to experimental spectra and used to estimate the mean cluster size realized in the experiment. The results indicate that size estimators working from stagnation conditions [R. Karnbach, M. Joppien, J. Stapelfeldt, J. W?rmer and T.M?ller, Rev. Sci. Instrum., 1993, 64, 2838] may underestimate the mean cluster size. 相似文献
402.
Jansson K Fristedt T Olsson A Svensson B Jönsson S 《The Journal of organic chemistry》2006,71(4):1658-1667
5-Chloro-N-ethyl-1,2-dihydro-4-hydroxy-1-methyl-2-oxo-N-phenyl-3-quinolinecarboxamide (laquinimod, 2) is an oral drug in clinical trials for the treatment of multiple sclerosis. The final step in the synthesis of 2 is a high-yielding aminolysis reaction of ester 1 with N-ethylaniline. An equilibrium exists between 1 and 2, and removal of formed methanol during the reaction is a prerequisite for obtaining high yields of 2 from 1. The reactivity of 1 and 2 is explained by a mechanistic model that involves a transfer of the enol proton to the exocyclic carbonyl substituent with concomitant formation of ketene 3. This proton transfer is especially facilitated for 2 because the intramolecular hydrogen bond to the carbonyl oxygen is weakened due to steric interactions. Both 1 and 2 undergo solvolosis reactions that obey first-order reaction kinetics, further supporting the theory that these two molecules are able to decompose unimolecularly into ketene 3. The solvent-dependent spectroscopic features of 2 indicate that the molecule mainly resides in two conformations. One conformation is favored in nonpolar solvents and is likely the result of intramolecular hydrogen bonding. The other conformation is favored in polar solvents and probably exhibits less intramolecular hydrogen bonding. 相似文献
403.
In this paper we extend the eliminant construction of Burchnall and Chaundy for commuting differential operators in the Heisenberg algebra to the q-deformed Heisenberg algebra and show that it again provides annihilating curves for commuting elements, provided q satisfies a natural condition. As a side result we obtain estimates on the dimensions of the eigenspaces of elements of this algebra in its faithful module of Laurent series. 相似文献
404.
V.P. Markevich A.R. Peaker B. Hamilton S.B. Lastovskii L.I. Murin J. Coutinho A.V. Markevich M.J. Rayson P.R. Briddon B.G. Svensson 《Physica B: Condensed Matter》2012,407(15):2974-2977
Disappearance of the divacancy (V2) and trivacancy (V3) complexes upon isochronal and isothermal annealing of electron irradiated Si:O crystals has been studied by means of deep level transient spectroscopy. The annealing studies have shown that the V2 and V3 defects are mobile in Si at T>200 °C and in oxygen-rich material are trapped by interstitial oxygen atoms so resulting in the appearance of V2O and V3O defects. The activation energies for diffusion of the V2 and V3 centers have been determined. Density functional modeling calculations have been carried out to investigate the migration and reorientation mechanisms of V3 in large silicon supercells. It is proposed that these comprise a sequence of transformations between V3(D3) and V3(C2v) configurations. 相似文献
405.
We use filtrations of the Grassmannian model to produce explicit algebraic formulae for all harmonic maps of finite uniton
number from a Riemann surface, and so all harmonic maps from the 2-sphere, to the unitary group for a general class of factorizations
by unitons. We show how these specialize to give explicit formulae for such harmonic maps to each of the classical compact
Lie groups and their inner symmetric spaces—the nonlinear σ-model of particle physics. Our methods also give an explicit Iwasawa
decomposition of the algebraic loop group. 相似文献
406.
Bastian Achenbach Erik Svensson Grape Dr. Mohammad Wahiduzzaman Sandra K. Pappler Marcel Meinhart Dr. Renée Siegel Prof. Dr. Guillaume Maurin Prof. Dr. Jürgen Senker Dr. A. Ken Inge Prof. Dr. Norbert Stock 《Angewandte Chemie (International ed. in English)》2023,62(29):e202218679
The solution chemistry of aluminum is highly complex and various polyoxocations are known. Here we report on the facile synthesis of a cationic Al24 cluster that forms porous salts of composition [Al24(OH)56(CH3COO)12]X4, denoted CAU-55-X, with X=Cl−, Br−, I−, HSO4−. Three-dimensional electron diffraction was employed to determine the crystal structures. Various robust and mild synthesis routes for the chloride salt [Al24(OH)56(CH3COO)12]Cl4 in water were established resulting in high yields (>95 %, 215 g per batch) within minutes. Specific surface areas and H2O capacities with maximum values of up to 930 m2 g−1 and 430 mg g−1 are observed. The particle size of CAU-55-X can be tuned between 140 nm and 1250 nm, permitting its synthesis as stable dispersions or as highly crystalline powders. The positive surface charge of the particles, allow fast and effective adsorption of anionic dye molecules and adsorption of poly- and perfluoroalkyl substances (PFAS). 相似文献